Electrochemical and Thermodynamic Properties of EuCl<sub>3</sub> and EuCl<sub>2</sub> in an Equimolar NaCl-KCl Melt

Kuznetsov, S. A.; Rycerz, L.; Gaune‐Escard, M.

doi:10.1515/zna-2001-1108

Cited by 42 publications

(51 citation statements)

References 11 publications

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“…According to Kuznetsov et al this is due to the decrease in the counterpolarization effect of the cation in the second coordination sphere, as the pull of the cation in the second coordination sphere decreases the bond strength of the metal-ligand interaction in the first coordination sphere will increase. 53 As the bond strength increases the complex becomes more stable and so it becomes more difficult to break that bond and allow the analyte to "hop" into the next vacant hole. As the "hopping" mechanism's contribution to the diffusion coefficient decreases there in an increase in the activation energy required for the movement of the analyte through the solution and decreasing the diffusion coefficient.…”

Section: Resultsmentioning

confidence: 99%

Electrochemistry of Europium(III) Chloride in 3 LiCl – NaCl, 3 LiCl – 2 KCl, LiCl – RbCl, and 3 LiCl – 2 CsCl Eutectics at Various Temperatures

Schroll

Chatterjee

Levitskaia

et al. 2017

J. Electrochem. Soc.

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Here we report the effect of changing the eutectic melt composition on the electrochemical properties of europium(III) chloride under pyroprocessing conditions. Stoichiometry of electron-transfer, redox potentials and diffusion coefficients were determined using various electrochemical and spectroelectrochemical techniques in four different eutectic mixtures (3 LiCl -NaCl, 3 LiCl -2 KCl, LiCl -RbCl, and 3 LiCl -2 CsCl) while varying the temperature of the melt. It was determined that Eu 3+ undergoes a one electron reduction to Eu 2+ in each melt at all temperatures evaluated. Within each of the melts a positive shift in the redox potential as well as an increase in the diffusion coefficient for Eu 3+ was observed as the temperature increased. Also observed was a positive shift in the redox potential and increase in the diffusion coefficient for Eu 3+ as the weighted average of the cationic radii the melt composition decreased. Pyroprocessing is one of the newest techniques for spent nuclear fuel reprocessing in which the separation is accomplished electrochemically in molten salt media at temperatures of >500• C. 1-3 Some of the advantages of pyroprocessing over the more traditional liquidliquid extraction techniques are that there is no organic solvent that is susceptible to radiolysis, 4,5 lack of pure plutonium product which provides less likelihood for proliferation, 6 generation of the U-Pu alloy product is ready for immediate fabrication into new fuel rods 7 and the ability to do a group separation of all actinides.8 There are also engineering related advantages such as amenability to scaling to the needs of the facility 9 and making the refinement vessel more compact. 10,11The most important information needed to understand pyroprocessing is accurate thermodynamic data for each of the analytes that may be found in used nuclear fuel in each of the possible eutectic melt compositions. We have chosen to investigate europium(III) chloride because it is a non-radioactive analog to the actinides which makes it safer to work with, it has the least negative redox potential of the lanthanides, and it undergoes a change in its absorption spectrum when it is reduced from Eu 3+ to Eu 2+ . 12 Prior research has been performed using europium(III) chloride and evaluating its thermodynamic properties in different melts, such as LiCl, 13 In this work we systematically evaluated the redox potentials and diffusion coefficients for europium(III) chloride using differential pulse voltammetry and cyclic voltammetry in three different eutectic salt compositions over a range of temperatures. The experiments were performed from 673 K to 1173 K in 3 LiCl -NaCl, LiCl -RbCl and 3 LiCl -2 CsCl. This data along with the results from our previous * Electrochemical Society Member.z E-mail: heinemwr@ucmail.uc.edu; sam.bryan@pnl.gov reports (Electrochemistry of Europium in 3 LiCl -2 KCl from 643 to 1123 K 29 and Spectroelectrochemistry of Europium in 3 LiCl -NaCl, 3 LiCl -2 KCl, LiCl -RbCl, and 3 LiCl −2 CsCl at 873 K 30 ) were analyzed ...

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Section: Resultsmentioning

confidence: 99%

Electrochemistry of Europium(III) Chloride in 3 LiCl – NaCl, 3 LiCl – 2 KCl, LiCl – RbCl, and 3 LiCl – 2 CsCl Eutectics at Various Temperatures

Schroll

Chatterjee

Levitskaia

et al. 2017

J. Electrochem. Soc.

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“…deposition of iron on iron deposits). In most cases, the deposition of metal ions on a solid electrode in chloride melts occurs under diffusion control [7,[14][15][16][17][18][19][20][21]. The obvious explanation for this is that the elevated temperatures at which chloride melts exist (∼500 • C and higher) provide the reactant with enough energy to easily overcome the kinetic (activation) barriers of the various reaction stages.…”

Section: Discussing a Plausible Mechanismmentioning

confidence: 99%

Electrodeposition of iron(II) on platinum in chloride melts at 700–750°C

Lugovskoy

Zinigrad

Aurbach

et al. 2009

Electrochimica Acta

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“…It was reported that the values of relative partial enthalpy of EuCl 3 mixing with alkali chloride melts are higher than that for EuCl 2 [23,24]. From the similar investigations, the equilibrium constants of metal-salt reaction 2Eu(III) + Eu !…”

Section: Selectivity Of Rementioning

confidence: 82%

Pyrochemical process for electrochemically base metals in molten halides combined countercurrent electromigration and electrowinning methods

Matsumiya

Matsuura

2005

Journal of Electroanalytical Chemistry

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Electrochemical and Thermodynamic Properties of EuCl₃ and EuCl₂ in an Equimolar NaCl-KCl Melt

Cited by 42 publications

References 11 publications

Electrochemistry of Europium(III) Chloride in 3 LiCl – NaCl, 3 LiCl – 2 KCl, LiCl – RbCl, and 3 LiCl – 2 CsCl Eutectics at Various Temperatures

Electrochemistry of Europium(III) Chloride in 3 LiCl – NaCl, 3 LiCl – 2 KCl, LiCl – RbCl, and 3 LiCl – 2 CsCl Eutectics at Various Temperatures

Electrodeposition of iron(II) on platinum in chloride melts at 700–750°C

Pyrochemical process for electrochemically base metals in molten halides combined countercurrent electromigration and electrowinning methods

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Electrochemical and Thermodynamic Properties of EuCl3 and EuCl2 in an Equimolar NaCl-KCl Melt

Cited by 42 publications

References 11 publications

Electrochemistry of Europium(III) Chloride in 3 LiCl – NaCl, 3 LiCl – 2 KCl, LiCl – RbCl, and 3 LiCl – 2 CsCl Eutectics at Various Temperatures

Electrochemistry of Europium(III) Chloride in 3 LiCl – NaCl, 3 LiCl – 2 KCl, LiCl – RbCl, and 3 LiCl – 2 CsCl Eutectics at Various Temperatures

Electrodeposition of iron(II) on platinum in chloride melts at 700–750°C

Pyrochemical process for electrochemically base metals in molten halides combined countercurrent electromigration and electrowinning methods

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Electrochemical and Thermodynamic Properties of EuCl₃ and EuCl₂ in an Equimolar NaCl-KCl Melt